Stronger European cooperation on defence would act as "a second life insurance policy" alongside the NATO alliance, French Foreign Minister Stephane Sejourne said Sunday.

In an interview with the German daily Die Welt, Sejourne called for greater "standardisation of weapons systems on a European level".

This did not mean having "competing standards" within NATO but "strengthening the European pillar" of the military alliance, Sejourne said.

"The development of the European defense industry should not be a substitute, but a complement" to NATO, the minister said.

"We have to take out a second life insurance policy alongside NATO," he said.

Concerns over the United States' commitment to NATO in the event of former president Donald Trump's re-election this year have precipitated discussions over Europe's military readiness.

Washington would remain a strong partner in defense, but Europe needed to develop its own "sovereignty and strategic autonomy", the minister said.

Sejourne echoed a message delivered by French President Emmanuel Macron in a speech at the Sorbonne University in Paris on Thursday.

Macron warned that Europe faced an existential threat from Russian aggression in the wake of the invasion of Ukraine.

He called on the continent to adopt a "credible" defence strategy less dependent on the United States.

Macron also said in his speech he would ask European partners for proposals in the coming months.

The contents of Macron's proposals would be discussed "intensively" with officials in Berlin, Sejourne said.

"France and Germany have a shared responsibility to set goals and act quickly and decisively," he said.

As an example, Sejourne cited progress on a joint battle tank project, with an agreement signed by the French and German defence ministers on Friday.

The project showed a movement towards becoming a "power in the field of European defense", Sejourne said.

The minister by contrast acknowledged that Germany was going a separate way from France on air defence, with Berlin pushing its own European Sky Shield Initiative.

While the German project looked abroad for the purchase of missiles, "France has its own air defense equipment and there is neither the intention nor the need to buy this foreign equipment," Sejourne said.

France supported efforts to strengthen air defence "but we are encouraging them to buy European equipment in the long term", the minister said.

"By becoming dependent, Europeans are preparing for the problems of tomorrow," Sejourne added.